<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Filter
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: PregReplace.php 23775 2011-03-01 17:25:24Z ralph $
 */

/**
 * @see Zend_Filter_Interface
 */
require_once 'Zend/Filter/Interface.php';

/**
 * @category   Zend
 * @package    Zend_Filter
 * @copyright  Copyright (c) 2005-2011 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Filter_PregReplace implements Zend_Filter_Interface {
	/**
	 * Pattern to match
	 * @var mixed
	 */
	protected $_matchPattern = null;
	
	/**
	 * Replacement pattern
	 * @var mixed
	 */
	protected $_replacement = '';
	
	/**
	 * Is unicode enabled?
	 *
	 * @var bool
	 */
	protected static $_unicodeSupportEnabled = null;
	
	/**
	 * Is Unicode Support Enabled Utility function
	 *
	 * @return bool
	 */
	static public function isUnicodeSupportEnabled() {
		if (self::$_unicodeSupportEnabled === null) {
			self::_determineUnicodeSupport ();
		}
		
		return self::$_unicodeSupportEnabled;
	}
	
	/**
	 * Method to cache the regex needed to determine if unicode support is available
	 *
	 * @return bool
	 */
	static protected function _determineUnicodeSupport() {
		self::$_unicodeSupportEnabled = (@preg_match ( '/\pL/u', 'a' )) ? true : false;
	}
	
	/**
	 * Constructor
	 * Supported options are
	 * 'match'   => matching pattern
	 * 'replace' => replace with this
	 *
	 * @param  string|array $options
	 * @return void
	 */
	public function __construct($options = null) {
		if ($options instanceof Zend_Config) {
			$options = $options->toArray ();
		} else if (! is_array ( $options )) {
			$options = func_get_args ();
			$temp = array ();
			if (! empty ( $options )) {
				$temp ['match'] = array_shift ( $options );
			}
			
			if (! empty ( $options )) {
				$temp ['replace'] = array_shift ( $options );
			}
			
			$options = $temp;
		}
		
		if (array_key_exists ( 'match', $options )) {
			$this->setMatchPattern ( $options ['match'] );
		}
		
		if (array_key_exists ( 'replace', $options )) {
			$this->setReplacement ( $options ['replace'] );
		}
	}
	
	/**
	 * Set the match pattern for the regex being called within filter()
	 *
	 * @param mixed $match - same as the first argument of preg_replace
	 * @return Zend_Filter_PregReplace
	 */
	public function setMatchPattern($match) {
		$this->_matchPattern = $match;
		return $this;
	}
	
	/**
	 * Get currently set match pattern
	 *
	 * @return string
	 */
	public function getMatchPattern() {
		return $this->_matchPattern;
	}
	
	/**
	 * Set the Replacement pattern/string for the preg_replace called in filter
	 *
	 * @param mixed $replacement - same as the second argument of preg_replace
	 * @return Zend_Filter_PregReplace
	 */
	public function setReplacement($replacement) {
		$this->_replacement = $replacement;
		return $this;
	}
	
	/**
	 * Get currently set replacement value
	 *
	 * @return string
	 */
	public function getReplacement() {
		return $this->_replacement;
	}
	
	/**
	 * Perform regexp replacement as filter
	 *
	 * @param  string $value
	 * @return string
	 */
	public function filter($value) {
		if ($this->_matchPattern == null) {
			require_once 'Zend/Filter/Exception.php';
			throw new Zend_Filter_Exception ( get_class ( $this ) . ' does not have a valid MatchPattern set.' );
		}
		
		return preg_replace ( $this->_matchPattern, $this->_replacement, $value );
	}

}
